JP4344603B2 - Wafer heating device - Google Patents

Description

The present invention mainly relates to a ceramic heater used to heat the wafer, for example, to produce a semiconductor thin film on a semiconductor wafer or a liquid crystal substrate or on a wafer such as a circuit board, which is applied on top Symbol wafer It is suitable for forming a resist film by drying and baking a resist solution.

  For example, a wafer heating apparatus is used to heat a semiconductor wafer (hereinafter abbreviated as a wafer) in a semiconductor thin film forming process, an etching process, a resist film baking process, and the like in a manufacturing process of a semiconductor manufacturing apparatus. Yes.

Conventional semiconductor manufacturing equipment used batch-type processing that forms a plurality of wafers together. To increase processing accuracy as the wafer size increases from 8 inches to 12 inches, , a technique called single wafer to be processed one not a one has been conducted in recent years. However, if the single wafer type is used, the number of processes per process is reduced, so that it is necessary to shorten the wafer processing time. For this reason, the wafer support member has been required to shorten the heating time of the wafer, speed up the wafer adsorption / desorption, and improve the heating temperature accuracy.

Among these, in forming the resist film on the wafer, one main surface of a plate-like ceramic body 32 made of ceramics such as aluminum nitride or silicon carbide as shown in FIG. A ceramic heater 31 having a structure in which a resistance heating element 35 and a power feeding part 36 are installed on the other main surface through an insulating layer 34 and a conduction terminal 37 is pressed and fixed to the power feeding part 36 by an elastic body 38 is used. It was done. The upper Symbol plate-shaped ceramic member 32 is secured by bolts 47 to the support 41, is further inserted temperature measurement element 40 in the interior of the plate-shaped ceramic member 32, thereby the plate-shaped ceramic body 32 the temperature predetermined for In order to maintain the temperature, the power supplied from the conduction terminal 37 to the resistance heating element 35 is adjusted. Further, the conduction terminal 37 is fixed to the plate-like structure portion 43 via an insulating material 39.

The support surface 44 inserted into the bottomed hole 45 is provided on the mounting surface 33 of the ceramic heater 31. When the wafer W is mounted on the mounting surface 33, the wafer W moves from the mounting surface 33. It is designed to be non-contact. Then, after the wafer W coated with a resist solution is placed on the support pins 44, the resistance heating element 35 is heated to heat the wafer W on the placement surface 33 via the plate-like ceramic body 32. The resist solution is dried and baked to form a resist film on the wafer W.

  Further, as the ceramic material constituting the plate-like ceramic body 32, nitride ceramics or carbide ceramics have been used.

In the heat treatment of a chemically amplified resist that has been used for the miniaturization of semiconductor wiring in recent years , a transient until the temperature is stabilized when the wafer W is replaced on the plate-like ceramic body 31. Characteristics and temperature variation within the wafer W surface are extremely important for chemical amplification treatment of the resist after exposure, and more precise and responsive temperature control is required than ever before.

Patent Document 1 discloses a method in which a nitride ceramic is used as the plate-like ceramic body 32 and the temperature is controlled while measuring the temperature near the heating element. When power is applied to the wafer heating device 31, the temperature of the mounting surface 33 of the wafer W starts to rise, but since the surface temperature of the outer peripheral portion of the mounting surface 33 is lowered, The resistance heating element 35 is designed so that the temperature distribution of the plate-like ceramic body 32 is uniform with respect to the set temperature in the steady state in consideration of the temperature drop due to the above. That is, in consideration of heat extraction from the outer peripheral portion of the mounting surface 33, the resistance of the outer peripheral portion of the resistance heating element 35 is made larger than the resistance of the central portion of the resistance heating element 35, and the temperature of the central portion and the outer peripheral portion is set. The plate-like ceramic body 32 has a small difference.
JP 2001-135460 A

  However, when the wafer W is replaced on the plate-like ceramic body 32, there is a problem that the amount of overshoot of the temperature in the wafer surface at the time of transition until the temperature becomes stable is large.

Further, in a wafer heating apparatus that heats a large wafer W of 300 mm or more, when heated to a set temperature, the temperature rise curves at the center and the outer periphery are different, and the temperature within the surface of the wafer W becomes constant. temperature stabilization time there was a long thread of challenges.

In the present invention, paying attention to the temperature behavior of the plate-like ceramic, a plurality of strip-like resistance heating elements are formed on the surface or inside of the plate-like ceramic body, and the plate-like ceramic body is positioned at a position corresponding to each heating resistor. In the wafer heating apparatus provided with a recess and provided with a temperature measuring element in the recess, at least one of the plurality of strip-like resistance heating elements disposed on the outermost periphery of the plate-like ceramic body is an area surrounding the resistance heating element comprising a temperature measuring element in the center of the power density in the vicinity of the temperature measurement element may be smaller than the average power density of the belt-shaped resistance heating element corresponding to the temperature measuring element.

  The power density in the vicinity of the temperature measuring element is 40 to 90% of the average power density of the resistance heating element.

Further, characterized in that fixed on the SL temperature measuring element on SL recess with a filler having a 8.3 to 150% of the thermal conductivity with respect to the thermal conductivity of the plate-like ceramic body.

The porosity of the upper Symbol filler is characterized in that 0.1% to 50%.

Further characterized in that the thermal expansion coefficient of the upper Symbol filler is 43 to 214% relative to the thermal expansion coefficient of the upper Symbol plate-shaped ceramic body.

According to the present invention, a plurality of strip-like resistance heating elements are formed on the surface or inside of a plate-like ceramic body, and a recess is provided at a position corresponding to each resistance heating element of the plate-like ceramic body. In the wafer heating apparatus including an element, at least one of the plurality of strip-shaped resistance heating elements disposed on the outermost periphery of the plate-shaped ceramic body includes a temperature measuring element at a central portion of a region surrounding the resistance heating element. the power density in the vicinity of the corresponding temperature measuring device, by which to be smaller than the average power density of the belt-shaped resistance heating element corresponding to the temperature measuring element, overshoot amount temperature becomes uniform wafer It has become smaller. In addition, it became the temperature stabilization time until the wafer temperature reaches the set temperature is rather short.

  In addition, even if the temperature cycle was repeated, the temperature stabilization time was less likely to change and showed excellent characteristics.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a cross-sectional view showing an example of a wafer heating apparatus 1 according to the present invention. One main part of a plate-like ceramic body 2 made of ceramics mainly composed of silicon carbide, boron carbide, boron nitride, silicon nitride, or aluminum nitride. The surface is a mounting surface 3 on which the wafer W is placed, and a resistance heating element 5 is formed on the other main surface 12 via an insulating layer 4 made of glass or resin.

  A pattern shape of the resistance heating element 5 may be any pattern shape that can heat the mounting surface 3 uniformly, such as a substantially arc shape or a substantially concentric circle shape or a spiral shape. In order to improve the thermal uniformity, it is preferable to divide the resistance heating element 5 into a plurality of resistance heating elements 5a, 5b, 5c, 5d, 5e, and 5f.

The plate-like ceramic body 2 has recesses 21a, 21b for holding the temperature measuring elements 10a, 10b, 10c, 10d, 10e, 10f surrounded by the resistance heating elements 5a, 5b, 5c, 5d, 5e, 5f. , 21c, 21d, 21e, and 21f are formed. Each of the temperature measuring elements 10 a, 10 b, 10 c, 10 d, 10 e, 10 f is a heat sensitive part located at the tip of the temperature measuring body 10. Each of these temperature measuring devices 10a, 10b, 10c, 10d, 10e, 10f are connected to the arithmetic unit 82 and the control unit 81, had a calculated voltage value that controls the arithmetic unit 82 rows, on this basis, control a predetermined voltage is sign pressurized for each resistance heating element 5 from the part 81, thereby making it possible to equalize the temperature of the wafer W.

  In addition, each resistance heating element 5 is formed with a power feeding portion 6 made of a material such as gold, silver, palladium, platinum, etc., and the conduction terminal 7 is pressed and fixed to the power feeding portion 6 via an elastic body 8. Is secured.

Further, bolts 17 are passed through the outer circumferences of the plate-like ceramic body 2 and the support 11, and an elastic body 8 and a washer 18 are interposed from the plate-like ceramic body 2 side, and a nut 19 is screwed to elastically support the support 11. Fixed. Thus, even if the support 11 is deformed when the temperature of the plate-like ceramic body 2 is changed or the temperature of the plate-like ceramic body 2 is changed by placing the wafer W on the mounting surface 3, the elasticity This is absorbed by the body 8, thereby preventing warpage of the plate-like ceramic body 2 and preventing a temperature difference from occurring on the surface of the wafer W.

  The support 11 includes a plate-like structure 13 composed of a plurality of layers and a side wall, and a conductive terminal 7 for supplying power to the resistance heating element 5 is provided on the plate-like structure 13 with an insulating material 9. The air injection port not shown is formed.

Further, embodiments of the present invention will be described in detail. FIG. 2 is a plan view of the plate-like ceramic body 2 as viewed from the resistance heating element 5 side. The plate-like ceramic body 2 has recesses 21 formed at positions corresponding to the resistance heating elements 5. As shown in FIG. 3, temperature measuring elements 10a, 10b, 10c, 10d , 10e, and 10f are arranged and filled and held by a filler 22 or the like.

That is, a plurality of strip-like resistance heating elements 5a, 5b, 5c, 5d, 5e, and 5f are formed on the surface or inside of the plate-like ceramic body 2, and the recesses 21a, 21b, 21c, 21d, 21e, and 21f are provided, and the recess 21 is provided with temperature measuring elements 10a, 10b, 10c, 10d , 10e, and 10f . In the wafer heating apparatus 1, at least one of the strip-like resistance heating elements 5a, 5b, 5c, and 5d disposed on the outermost periphery of the plate-like ceramic body 2 is used. , 5d, for example, resistive heating elements 5a, the power density in the vicinity of the corresponding temperature measuring device 10a is, are smaller than the average power density of the strip-shaped resistance heating element 5a.
The reason is that when the wafer W cooled to room temperature is placed on the plate-like ceramic body 2, the temperature of the plate-like ceramic body 2 is lowered by the wafer W. At this time, the temperature of the plate-like ceramic body 2 has a lower power density in the central portion than in the outer peripheral portion. Accordingly, the power application time in the central part is longer than the power application time in the outer peripheral part, so that the rise in temperature rises suddenly and overshoots. Therefore the temperature of the wafer W was not long temperature stabilization time to stabilize. That is, in the present invention, the time until the temperature of the wafer W is stabilized can be shortened by reducing the power density around the temperature measuring element 10a.

  The power density indicates a power value input per unit area of each part of the surface 12 where the resistance heating element 5a is formed on the plate-like ceramic body 2. The average power density is a value obtained by dividing the power value obtained from the total resistance value and current of the resistance heating element 5a by the heating area where the resistance heating element 5a is formed. In general, the heating area of the resistance heating element 5a is a boundary line between adjacent resistance heating elements 5b, 5d, 5e, and 5f.

Next, a method for calculating the power density near the temperature measuring element 10a will be described. First, the vicinity of the measuring Yutakamoto child 1 0a is a part of the resistance heating element 5a adjacent to example temperature measuring element 10a and the center points P1, P2 of the part of the heat generating resistor 5a in proximity to the outside, on a straight line passing through the center of the temperature measurement element 1 0a, the distance between the upper Symbol two center points P1, P2 and the M, and in parallel with the resistance heating element 5a of the strip pass over SL center point P1 or P2 2 the area defined by the center line in the book, shows the region 8 3 surrounded above SL 2 centerlines length M. Also, the region except for the recessed portion 21 from the region 8 3 and region 8 4. Then, the power density in the vicinity of the temperature measuring element 10a, 2 present area a part of the resistance value and the power value obtained from the current flowing therein in the region 8 4 of the resistance heating elements 5a of the regions 8 4 The value divided by.

  Further, the length M is desirably a region that is 1.5 to 5 times the diameter of the concave portion 21 of the plate-like ceramic body.

If the vicinity is smaller than 1.5 times the diameter of the concave portion 21 of the plate-like ceramic body, the temperature difference between the temperature measuring element and the entire temperature is small, so that the effect of improving the temperature rise characteristics is small. On the other hand, if it is larger than 5 times, the temperature difference between the vicinity of the temperature measuring element and other regions becomes undesirably large. That is, the length of M, which is the range in the vicinity of the temperature measuring element, is desirably a region that is 1.5 to 5 times the outer diameter of the recess 21 of the temperature measuring element, In this case, the sensitivity in the vicinity of the temperature measuring element can be increased. In other words, it is possible to equalize the Atsushi Nobori curve of the inner and outer resistive heating elements, temperature of U E wafer W can be further reduced time to stabilize.

More preferably, the power density in the vicinity of the temperature measuring element 10a is 40 to 90% of the power density of the strip-shaped resistance heating element 5a. If the power density ratio in the vicinity of the temperature measuring element 10a is less than 40%, if the temperature of the plate-like ceramic body 2 is low, the temperature is transmitted to the control unit, the power application time becomes long, and the plate-like ceramic body 2 is transferred to the wafer W. heat transfer (radiation heat) becomes too large, resulting in high Kuna' temperature of the wafer W than the predetermined temperature. The so-called overshoot amount increases. Larger than 90% Conversely, temperature measuring element 10a is determined to decrease the temperature of the plate-shaped ceramic body 2 of the outer peripheral portion is small, since the time to mark pressure output is shortened, a smooth Atsushi Nobori curve. Thus, since the sign pressurizing power is long central portion of the heating is fast, the temperature is the temperature stabilization time to stabilize unfavorably more than 50 seconds.

Incidentally, preferably, all of the outermost resistive heating elements 5a to 5d, it is preferable that the power density in the vicinity of its corresponding temperature measuring device is made smaller than the average power density of the resistance heating elements 5a to 5d.

The adjustment of the power density, the line width and thickness of the resistance heating element, will rows by changing the line spacing, and the like.

As the temperature measuring elements 10a, 10b, 10c, 10d , 10e, and 10f , a temperature measuring element, a resistance temperature detector, or the like can be used. As for the material, if it is a thermocouple, Pt / Rh—Pt / Rh, Pt / Rh—Pt, Ni / Cr / Si—Ni / Si / Mg, Ni / Cr—Al / Mn, Ni / Cr If the Cr-Cu / Ni system, Cu-Cu / Ni system, W-Re system, etc. are also resistance temperature detectors, a Pt resistance element can be used, and the one suitable for the operating atmosphere and temperature should be used. It only has to be selected. For example, when used in the atmosphere at 300 ° C. or lower, a Ni / Cr—Al / Mn system, a Pt / Rh—Pt system, a Ni / Cr—Cu / Ni system, or the like is desirable, and in a reducing atmosphere, Fe-Cu / Ni system or the like is desirable.

Further, as shown in FIG. 3, it is desirable to use a resistance temperature detector such as a Pt resistance element for the temperature measuring elements 10a, 10b, 10c, 10d , 10e, and 10f . It is also effective to use a resistive element coated with an insulating material such as a resin coat, a glass coat, or a ceramic coat. Moreover, you may use an insulation sleeve etc. after a filling holding | maintenance part as needed.

The recess 21a, 21b, 21c, 21d, 21e, the area of the opening of ^21f, it is desirable to 1mm ² ~30mm 2. If the area of the openings of the recesses 21a, 21b, 21c, 21d , 21e, 21f is smaller than 1 mm ² , unevenness occurs in the installation of the temperature measuring elements 10a, 10b, 10c, 10d , 10e, 10f and the filling of the filler 22. The temperature measurement easily varies. On the other hand, if it is larger than 30 mm ² , the gap between the resistance heating elements 5 becomes large, and the temperature distribution on the surface of the wafer W becomes large.

The depth d of the recesses 21a, 21b, 21c, 21d , 21e, and 21f is preferably (1/4) t ≦ d ≦ (3/4) t with respect to the thickness t of the plate-like ceramic body 2. . And the deep d of (1/4) t is less than, deviation occurs in the temperature measuring for distances become longer in the wafer mounting surface, not raised the wafer to the desired temperature. Further, (3/4) becomes greater than t, undesirable since the amount of overshoot temperature is too large reversed.

Further, the distance L between the bottom surfaces of the recesses 21a, 21b, 21c, 21d , 21e, and 21f and the tips of the temperature measuring elements 10a, 10b, 10c, 10d , 10e, and 10f is 0 ≦ L ≦ 1.0 mm. Is more desirable. When the distance L exceeds 1 mm, the responsiveness of temperature detection is delayed and the overshoot amount becomes large. However, by setting the distance L to 1.0 mm or less, the overshoot amount becomes smaller.

Furthermore, the size of the temperature measuring elements 10a, 10b, 10c, and 10d inserted into the recesses 21a, 21b, 21c, 21d , 21e, and 21f is preferably 30 mm ² or less. If it is larger than 30 mm ² , the heat capacity of the temperature measuring elements 10a, 10b, 10c, 10d , 10e, and 10f itself becomes too large, so that heat is drawn through the strands, resulting in a delay in temperature detection and a large overshoot amount. Since it becomes too much, it is not preferable.

In addition, a recess 21 is provided at a position corresponding to each resistance heating element 5 of the plate-shaped ceramic body 2, and the positions of the temperature measuring elements 10 a, 10 b, 10 c, 10 d of the recess 21 are the outermost periphery of the plate-shaped ceramic body 1. It is desirable to be located in the vicinity of the center of gravity G of the region R surrounding the plurality of strip-like resistance heating elements 5 disposed in the area. When the distance from the center of gravity G to the center of the concave portion 21 at the outermost peripheral portion is 30% or more of the maximum length L in the diameter direction of the plate-like ceramic body 2 in the region R, the outer resistance heating element will under the influence of easily gathered, rising of the outer peripheral portion is slow, a long time to stabilize Runode undesirable.

Further, the filler 22 used for holding the temperature measuring elements 10 a, 10 b, 10 c, 10 d , 10 e, 10 f in the recess 21 is 8.3 to 150% of the thermal conductivity of the plate-like ceramic body 2. Use the rate. When the thermal conductivity ratio is less than 8.3%, the Joule heat generated from the resistance heating element 5 is measured via the filler 22 with respect to the speed at which the Joule heat generated from the resistance heating element 5 is transmitted to the mounting surface 3 via the plate-like ceramic body 2. Since the speed transmitted to the temperature elements 10a, 10b, 10c, 10d , 10e, and 10f is too slow, the temperature detection is delayed and the amount of overshoot becomes too large. Further, Exceeding 150%, relative to the rate at which Joule heat is transmitted to the surface 3 the mounting through the plate-shaped ceramic body 2, temperature measuring element 10a via the filler 22, 10b, 10c, 10d, 10e, 10f Since the speed transmitted to the temperature is too high, the temperature measuring elements 10a, 10b, 10c, 10d , 10e, and 10f detect the temperature before the mounting surface 3 reaches a predetermined temperature, and supply power to the resistance heating element 5 This is not preferable because the temperature rise is delayed as a result. More preferably, it is better to use a filler having a thermal conductivity of 25 to 100% with respect to the thermal conductivity of the plate-like ceramic body 2.

Furthermore, the porosity of the upper Symbol fillers, 0. It is preferable to set it in the range of 1 to 50%. When the porosity is less than 0.1%, the flexibility of the filler 22 is impaired, and the thermal stress generated between the plate-like ceramic body 2 and the filler 22 when a temperature cycle is applied to the wafer heating device 1. If it is used for a long period of time, the filler 22 is peeled off from the plate-like ceramic body 2 and accurate temperature control cannot be performed. The unfavorable 50% is exceeded and pores acts as a heat insulating material, since the measured temperature is stabilized not quite. More preferably, better to the porosity and 0.5 to 25%, Overclocking shoot biomass durability increases becomes smaller favorable.

Adjustment of the porosity may for a while left to defoaming after filling room temperature with rows of Unado, it is preferable to adjust by removing air bubbles engulfed. Moreover, as a method of increasing the porosity, it can be increased by adjusting the number of rotations and time when a filler such as carbon or metal powder is mixed into the resin.

Furthermore, the thermal expansion coefficient of the filler 22 is desirably in the range of 50 to 200% with respect to the thermal expansion coefficient of the plate-like ceramic body 2. If the thermal expansion coefficient of the filler 22 falls outside the above range, it is not preferable because the temperature measuring element 10 protrudes from the recess 21 due to stress due to the difference in thermal expansion coefficient when heating and cooling are repeated. Also, wettability with the plate-like ceramic body 2 is important. If a gap appears between the temperature measuring element 10 and the recess 21, the gap acts as a heat insulating layer, and an accurate temperature cannot be measured. This is not preferable because it takes a long time to reach a predetermined temperature. More preferably, a filler 22 having a thermal expansion coefficient of 70 to 140% with respect to the thermal expansion coefficient of the plate-like ceramic body 2 is used.

Moreover, as the filler 22 used in the present invention, a heat-resistant resin in which powder having high thermal conductivity such as carbon, aluminum nitride, boron nitride, or metal powder is dispersed can be used. Thus, since the filler 22 of the type in which the high thermal conductive powder is dispersed in the resin has good fluidity, workability at the time of filling is improved. As the type of resin, it is preferable to use a resin having a heat resistant temperature of 300 ° C. or higher, such as polyimide, polyamide, and polyimideamide. On the other hand, when an epoxy resin having a heat resistant temperature of 200 ° C. or less, a silicon resin or the like is used, the fixing strength is high, but the resin becomes carbonized and becomes brittle during use, and the temperature measuring elements 10a, 10b, 10c, 10d , 10e 10f peels off and the accurate temperature cannot be measured. Further, cement such as alumina cement can be used as the filler 22 if it is filled so as not to impair the thermal conductivity.

  Further, in FIG. 1, the metal support 11 has a side wall portion and a plate-like structure 13, and the plate-like structure 13 has an opening corresponding to 5 to 50% of the area. . In addition, the plate-like structure 13 includes, as necessary, a conduction terminal 7 for conducting electricity with the power feeding portion 6 for feeding power to the resistance heating element 5 of the plate-like ceramic body 2, the plate-like ceramic body 2. A gas outlet for cooling the temperature sensor 10 and a temperature measuring element 10 for measuring the temperature of the plate-like ceramic body 2 are installed.

Also, the lift pins not illustrated is installed vertically movably in the support member 11, or placed on surface 3 mounting the the wafer W, it is used in order to lift or from mounting surface 3. In order to heat the semiconductor wafer W by the wafer heating apparatus 1, the wafer W carried to the upper side of the mounting surface 3 by a transfer arm (not shown) is supported by lift pins, and then the lift pins are lowered to move the wafer W. Is placed on the mounting surface 3. Next, the power supply unit 6 is energized to cause the resistance heating element 5 to generate heat, and the wafer W on the mounting surface 3 is heated via the insulating layer 4 and the plate-like ceramic body 2.

  At this time, according to the present invention, the plate-like ceramic body 2 is made of a silicon carbide sintered body, a boron carbide sintered body, a boron nitride sintered body, a silicon nitride sintered body, or an aluminum nitride sintered body. Therefore, deformation is small even when heat is applied, and the plate thickness can be reduced. Therefore, the temperature rise time until heating to a predetermined processing temperature and the cooling from the predetermined processing temperature to cooling to room temperature. The time can be shortened, the productivity can be increased, and the thermal conductivity of 60 W / (m · K) or more can be quickly transmitted, so the Joule heat of the resistance heating element 5 can be quickly transmitted even with a thin plate thickness, The temperature variation of the mounting surface 3 can be extremely reduced. In addition, since it does not generate gas by reacting with moisture in the atmosphere, even if it is used to attach a resist film on a semiconductor wafer, it does not adversely affect the structure of the resist film, and fine wiring Can be formed at high density.

By the way, in order to satisfy such characteristics, the plate thickness of the plate-like ceramic body 2 is preferably set to 1 mm to 7 mm. This is because if the plate thickness is less than 1 mm, the plate thickness is too thin, so that the effect as the plate-like ceramic body 2 of leveling the temperature variation is small, and the Joule heat variation in the resistance heating element 5 is placed as it is. to appear as the temperature variation of the surface 3, because the temperature control of the mounting surface 3 is difficult, when the plate thickness conversely obtain ultra the 7 mm, too large thermal capacity of the plate-shaped ceramic body 2, a predetermined process temperature This is because the temperature raising time until heating to a long time and the cooling time at the time of temperature change become long, and the productivity cannot be improved.

  Further, in the wafer heating apparatus 1 of the present invention described in detail above, as shown in FIG. 1, a resistance heating element 5 is formed on the surface of the plate-like ceramic body 2 via an insulating layer 4. Since it is exposed, the resistance heating element 5 can be trimmed to adjust the resistance value so that the temperature distribution on the mounting surface 3 becomes uniform according to the use conditions and the like.

Moreover, as ceramics which form the plate-shaped ceramic body 2, what has as a main component any one or more of silicon carbide, boron carbide, boron nitride, silicon nitride, and aluminum nitride can be used. As the silicon carbide sintered body, a sintering aid containing boron (B) and carbon (C) as sintering aids for the main component silicon carbide, or a sintering aid for the main component silicon carbide. containing an alumina _(Al 2 _{O 3)} and yttria _{(Y 2 O} 3) as an agent, 1900-2200 can be used a sintered body fired at ° C., also silicon carbide which mainly of type α Or any of those mainly composed of β-type.

  The boron carbide sintered body is obtained by mixing 3 to 10% by weight of carbon as a sintering aid with boron carbide as a main component, and performing hot press firing at 2000 to 2200 ° C. be able to.

In the boron nitride sintered body, 30 to 45% by weight of aluminum nitride and 5 to 10% by weight of rare earth element oxide are mixed as a sintering aid with respect to boron nitride as a main component, and 1900 to 2100. A sintered body can be obtained by hot-press firing at ° C. As another method for obtaining a sintered body of boron nitride, there is a method in which borosilicate glass is mixed and sintered. However, this is not preferable because the thermal conductivity is remarkably lowered.

The silicon nitride sintered body is composed of 3 to 12% by weight of rare earth element oxide and 0.5 to 3% by weight of Al ₂ O ₃ as a sintering aid with respect to silicon nitride as a main component. A sintered body can be obtained by mixing SiO ₂ so that the amount of SiO ₂ contained in the bonded body is 1.5 to 5% by weight and performing hot press firing at 1650 to 1750 ° C. Here, the SiO ₂ amount indicated, the SiO ₂ generated from oxygen impurity contained in the silicon nitride in the raw material, and SiO ₂ as an impurity contained in other additives, the sum of the SiO ₂ was deliberately added is there.

In addition, as the aluminum nitride sintered body, a rare earth element oxide such as Y ₂ O ₃ or Yb ₂ O ₃ as an auxiliary sintering agent and an alkaline earth such as CaO as necessary with respect to the main component aluminum nitride. It is obtained by adding a metal oxide and mixing well, processing it into a flat plate shape, and then firing at 1900 to 2100 ° C. in nitrogen gas.

These sintered bodies are used by selecting a material depending on the application. For example, when used for drying a resist film, a nitride reacts with moisture to generate ammonia gas, which cannot be used because it adversely affects the resist film. In the case of a wafer heating apparatus for CVD that may be used at a high temperature of about 800 ° C., the material of the boron nitride based containing a large amount of glass will deform the plate-shaped ceramic body 2 is in use, Hitoshi Thermal properties may be impaired.

Furthermore, the main surface opposite to the mounting surface 3 of the plate-shaped ceramic body 2 has a flatness of 20 μm or less and a surface roughness of the center line average roughness from the viewpoint of improving the adhesion with the insulating layer 4 made of glass or resin. (Ra) is 0. It is preferable to polish to 1 to 0.5 μm.

On the other hand, when the silicon carbide sintered body is used as the plate-like ceramic body 2, the insulating layer 4 that maintains insulation between the plate-like ceramic body 2 and the resistance heating element 5 having some conductivity is made of glass or resin. it is possible to use, in the case of using a glass, the thickness thereof can not be maintained insulating withstand voltage is below 1.5kV in less than 100 [mu] m, the thickness conversely obtain ultra the 500 [mu] m, the plate-shaped ceramic body 2 Since the thermal expansion difference between the silicon carbide sintered body and the aluminum nitride sintered body to be formed becomes too large, cracks are generated and the insulating layer 4 does not function. Therefore, when glass is used as the insulating layer 4, the thickness of the insulating layer 4 is preferably formed in a range of 10 0 to 500 [mu] m, and desirably be formed in a range of 15 0 to 400 [mu] m.

If the surface of the plate-shaped ceramic body 2 made of silicon carbide sintered body to form an insulating layer 4, by oxidizing the pre-surface, after forming an oxide film composed of SiO ₂ of 0.01~2μm thickness Further, an insulating layer 4 is formed on the surface . When the plate-like ceramic body 2 is formed of a ceramic sintered body mainly composed of aluminum nitride, an insulating layer made of glass is used to improve the adhesion of the resistance heating element 5 to the plate-like ceramic body 2. 4 is formed. However, when sufficient glass is added in the resistance heating element 5 and sufficient adhesion strength can be obtained by this, it can be omitted.

Next, when a resin is used for the insulating layer 4, when the thickness is less than 30 μm, the withstand voltage is less than 1.5 kV and the insulation cannot be maintained, and the resistance heating element 5 is trimmed by laser processing or the like. will damage the insulating layer 4, the longer functions as an insulating layer 4, the thickness conversely obtain ultra the 400 [mu] m, the more the amount of evaporation of the solvent and water generated during the resin baking, the plate-shaped ceramic body 2 A bubble-like peeling portion called a bulge is formed between them, and heat transfer is deteriorated by the presence of this peeling portion, so that the soaking of the mounting surface 3 is inhibited. Therefore, when using the resin as the insulating layer 4, the thickness of the insulating layer 4 is preferably formed in the range of 3 0 to 400 [mu] m, and desirably be formed in a range of 6 0 to 200 [mu] m.

  Moreover, as resin which forms the insulating layer 4, when the heat resistance of 200 degreeC or more and the adhesiveness with the resistance heating element 5 are considered, a polyimide resin, a polyimide amide resin, a polyamide resin etc. are preferable.

The means for depositing a dielectric layer 4 made of glass or resin on the plate-shaped ceramic body 2, dropping an appropriate amount on the Symbol glass paste or resin paste in the center of the plate-shaped ceramic body 2, by a spin coating method stretched uniformly or applied, or screen printing method, dipping method, was uniformly applied by a spray coating method or the like, in the glass paste at a temperature of 6 00 ° C., in the resin paste 3 00 ° C. Bake at the above temperature. Further, when glass is used as the insulating layer 4 heats the plate-shaped ceramic body 2 made of pre-silicon carbide sintered body or boron carbide sintered body to a temperature of about 1200 ° C., depositing a dielectric layer 4 By oxidizing the surface, the adhesion with the insulating layer 4 made of glass can be enhanced.

Furthermore, as the resistance heating element 5 to be deposited on the insulating layer 4, a simple metal such as gold (Au), silver (Ag), copper (Cu), palladium (Pd), etc. is directly deposited by a vapor deposition method or a plating method. or deposited, or upper Symbol simple metal or rhenium oxide (Re 2 O _3), prepared resin paste and glass paste containing an oxide of lanthanum manganate (LaMnO ₃₎ such as a conductive material, a predetermined pattern after printing by screen printing or the like, the upper Kishirube material may be combined in a matrix made of resin or glass by baking. When glass is used as the matrix, but may be any one of crystallized glass and amorphous glass, it is preferable to use a crystallized glass in order to suppress the change in the resistance value due to thermal cycling.

However, when using the resistance heating element 5 Ginmata is copper, because there is a possibility that migration occurs, in such a case, the same material as the insulating layer 4 so as to cover the resistive heating element 5 or the resistance heating element A protective film made of a material equivalent to the matrix component 5 may be coated with a thickness of about 30 μm.

For the plate-like ceramic body 2 of the type incorporating the resistance heating element 5, it is preferable to use an aluminum nitride sintered body having high thermal conductivity and high electrical insulation. In this case, after sufficiently mixing the raw material appropriately containing sintering aid as a main component of aluminum nitride was formed into a disk shape, and printing a paste made of W or WC on its surface to the pattern of the resistance heating element 5 Then, after another aluminum nitride molded body is stacked and adhered thereon, it is fired in a nitrogen gas at a temperature of 1900 to 2100 ° C., whereby the plate-like ceramic body 2 incorporating the resistance heating element 5 can be obtained. Conduction from the resistance heating element 5 may be performed by forming a through hole in an aluminum nitride base material, filling a paste made of W or WC , and then firing the electrode so as to be fired.

Examples of the properties of the glass forming the insulating layer 4 may be either crystalline or amorphous, for example in the case of using the resist drying, of at and 20 ° C. to 200 DEG ° C. heat resistant temperature 200 ° C. or higher it is preferable that the thermal expansion coefficient in a temperature range is appropriately selected and used those in the range of -5~ + 5 × 10 -7 ^/ ℃ with respect thermal expansion coefficient of the ceramic constituting the plate-shaped ceramic body 2. That is, when a glass having a thermal expansion coefficient is outside the above above range, since the difference in thermal expansion between the ceramic forming the plate-shaped ceramic body 2 is too large, at the time of cooling after baking of glass, plate-shaped ceramic body 2 or warpage occurs, defects as cracks and peeling and the like because easily or to occur.

Thermal conductivity silicon carbide sintered body of the 100W / (m · K), thickness 4 mm, the plate-like and the plate-shaped ceramic having an outer diameter of 300mm and a plurality fabrication, the temperature of each block of the resistance heating element was processed recess depth 2.3 mm × 1 mm in diameter for temperature measurement element disposed for measuring. Thereafter, an oxidation film is formed on the surface by oxidation treatment at 1000 ° C. for 2 hours, and an insulating layer is deposited on one main surface of each plate-like ceramic body. the terpineol kneaded to glass paste was prepared as laid by a screen printing method, after drying the organic solvent is heated to 0.99 ° C., subjected to 30 minutes degreased at 550 ° C., further 700 to 900 ° C. the rows that Ukoto baked at a temperature to form an insulating layer having a thickness of 200μm made of glass.

Then, for depositing a resistance heating element on the insulating layer, the Au powder and Pt powder glass paste was added as a conductive material, after printing a predetermined pattern by screen printing and heated to 0.99 ° C. the organic solvent was dried, was subjected to 30 minutes degreasing treatment at 550 ° C., by the row of Ukoto baked at a temperature of 700 to 900 ° C., the thickness was formed a resistance heating element 50 [mu] m. Resistive heating element has a structure of six was divided into four central portion two and the outer peripheral portion in a circumferential direction. In order to confirm the influence of the power density by the resistance heating element around the temperature measuring element, the wafer heating apparatus having a power density around the temperature measuring element of 20% to 120% with respect to the average power density of the individual resistance heating elements. Was made. After scolding, by fixing the power supply unit with a conductive adhesive to the resistance heating element was fabricated plate-shaped ceramic body.

Thereafter, the temperature measuring element composed of a resistor element in a recess of the temperature measuring portion of the resistance heating element, the tip temperature measuring unit is embedded in contact with the bottom of the upper Symbol recess, filled with the filler between. As this filler, resin (polyimide) was poured and fixed.

  In addition, as the support, two plate-like structures made of stainless steel with a thickness of 2.5 mm having an opening formed on 30% of the main surface are prepared, and ten conductive terminals are predetermined on one of these plates. And a support body was prepared by fixing it with a side wall portion made of stainless steel by screw tightening.

Thereafter, on the upper Symbol support, heating the substantially central portion of the pattern forming unit to form a recess in, the temperature measuring element is placed, superimposed inorganic holding fixed plate-shaped ceramic body with a filler, its periphery A wafer heating apparatus is provided in which the part is screwed through an elastic body.

  And the electric power feeding part which consists of gold paste was formed by the transfer method, and it baked at 900 degreeC.

Here, the influence of the power density ratio and the arrangement of the temperature measuring elements was investigated. The material of the plate-like ceramic body is aluminum nitride, and the power density ratio of each wafer heating device is 90%, 100%, 110%, from the center of gravity G of the belt-like heating element at the position of the concave portion of the plate-like ceramic body. The wafer heating device was manufactured by changing the deviation amount Y to 0%, 10%, 20%, and 30% of the width in the diameter direction of the plate-shaped ceramic body of the resistance heating element. Then, the conductive terminal of the wafer heating device thus obtained is energized and held at 150 ° C., and the temperature distribution on the wafer surface placed on the mounting surface is set to 1/3 of the wafer center and the wafer radius. And the temperature controller's set temperature is corrected for each resistance heating element so that the total temperature variation of 17 points with 16 points of 8 divided points on the circumference of 2/3 is within 1 ° C, and the setting variation is confirmed did. In addition, after removing the wafer and holding it for 60 minutes or more only with the wafer heating device, the wafer W maintained at room temperature is charged into the heating device and placed on the mounting surface until the wafer W is stabilized at 150 ° C. temperature stabilization time overshoot amount you and to stabilize the 0.99 ± 0.5 ° C. of the measures One not a five each sample was the maximum value and the measured value.

Each result is as shown in Table 1.

As can be seen from the results shown in Table 1, Sample No. The 1 and 2 wafer heating devices detect that the temperature of the resistance heating element is high because the power density around the temperature measuring element is too high, and the time it takes to output is shortened, so the temperature at the outer periphery rises slowly. overshoot amount 2 ℃ and becomes large as 2.6 ° C., the temperature stabilization time is 61 seconds, 67 seconds and rather long, is not preferable.

On the other hand, the circumferential displacement amount X of the center of gravity G of the belt-like heating element is 20 degrees at the position of the concave portion of the plate-like ceramic body, and the radial displacement amount Y is 20 inside the width of the resistance heating element of the concave portion. %, Outer 20%, and power density ratio smaller than 100%. In Nos. 3 to 5, the overshoot amount was less than 2 ° C., the temperature stabilization time was as small as 48 seconds or less , and good transient characteristics were exhibited.

Was also tested by changing the arrangement of the temperature measurement element results, the position of the recess of the plate-shaped ceramic body, Sample No. shift amount Y is 30% from the center of gravity G of the strip heating element 6, compared somewhat long Ino time and 51 seconds to c E c temperature stabilizes, Sample No. 4 and 5 were 45 seconds and 46 seconds.

Here, the influence of the arrangement of the temperature measuring element was investigated. The material of the plate-like ceramic body is aluminum nitride, and the region in the vicinity of the temperature measuring element of the resistance heating element of the plate-like ceramic body of each wafer heating device is 1.25, 1.5, the resistance adjusting rows that have changed to 5, 7.5 times the area, to produce a wafer heating apparatus. The temperature measuring element was positioned at the center of gravity of each resistance heating element. Thus by energizing the conductive terminals of the resulting wafer heating device to hold at 0.99 ° C., in the same manner as in Example 1, and the adjustment of the temperature line Tsu name. In addition, after removing the wafer and holding it for 60 minutes or more only with the wafer heating device, the wafer W maintained at room temperature is put into the heating device and is stabilized at 150 ± 0.5 ° C. from the moment it is placed on the mounting surface. the temperature stabilization time, measures not a One each sample five times to the maximum value and the measured value.

The results are shown in Table 2.

As can be seen from the results shown in Table 2, Sample No. 21 and 24, have not been improved time to stabilize. In contrast, the region near the temperature measuring device is to 凹径, 1. No. 5-5 times No. 22 and 23, time to stabilize is 43 seconds or less and rather short, was preferred.

Here, the influence of the power density ratio in the vicinity of the temperature measuring element was investigated. The material of the plate-shaped ceramic body is aluminum nitride, the shift amount Y from the center of gravity G of the temperature measuring element and 0%, 3 power density ratio (average power density of the power density / resistance heating element near temperature measuring element) 0 A wafer heating device was made between ˜95%.

Thus by energizing the conductive terminals of the resulting wafer heating device to hold at 0.99 ° C., in the same manner as in Example 1, and the adjustment of the temperature line Tsu name. In addition, after removing the wafer and holding it for 60 minutes or more only with the wafer heating device, the wafer W maintained at room temperature is put into the heating device and is stabilized at 150 ± 0.5 ° C. from the moment it is placed on the mounting surface. the temperature stabilization time, measures not a One each sample five times to the maximum value and the measured value.

The results are shown in Table 3.

As can be seen from the results shown in Table 3, the sample No. In the wafer heating apparatus 31, a wafer W maintained at room temperature is placed on a mounting surface heated to 150 ° C., and the overshoot amount of the wafer W from the moment when the wafer W is placed on the mounting surface until it stabilizes at 150 ° C. is 1. .7 ° C. somewhat rather large, also slightly off-length stable to time even 43 seconds to 0.99 ± 0.5 ° C.. This is because the power density around the temperature measuring device is less than the average power density, detects the initial temperature is low, is then because the time to output continues for a long time, overshoot amount would exceed the 0.99 ° C. 1.7 It is thought that it became large with ℃.

Sample No. 32 temperature stabilization time is 43 seconds, overshoot amount was slightly large as 1.1 ° C..

In contrast, sample no. 32 to 36 is the amount of overshoot is less than a temperature 1.5 ° C., the temperature stabilization time is 42 or less and rather short, exhibited good transient characteristics.

  Therefore, it has been found that the power density in the vicinity of the temperature measuring element is preferably 40 to 90% of the average power density of the resistance heating element.

Here, the influence of the thermal conductivity of the filler for fixing the temperature measuring element was investigated. As the filler, powders of Al, Cu, Ni, etc. having a thermal conductivity of 230 to 420 W / (m · K) are appropriately dispersed so that the thermal conductivity is 1 to 150 W / (m · K). The resin (polyimide), ceramic cement (alumina cement), and brazing material (Au—Cu brazing, Ag—Cu brazing) were poured and fixed. Using the thus adjusted if the filler, the temperature measuring element is fixed in the recess of each plate-shaped ceramic body to produce a wafer heating apparatus.

  The power density around the temperature measuring element of the manufactured wafer heating apparatus was 80% with respect to the average power density of the individual resistance heating elements.

The adjustment of the temperature line Tsu name in the same manner as in Example 1. In addition, the wafer W maintained at room temperature is put into a wafer heating apparatus and the overshoot amount of the wafer W from the moment it is placed on the mounting surface until it stabilizes at 150 ° C., and is stabilized at 150 ± 0.5 ° C. The temperature stabilization time until was measured. Furthermore, the temperature cycle in which the temperature was raised from 40 ° C. or lower to 250 ° C. in 2 minutes and forced air cooling to 40 ° C. or lower in 3 minutes was performed 10,000 cycles. Thereafter, the wafer W maintained at room temperature is placed on the mounting surface at 150 ° C. of the wafer heating apparatus, and the overshoot amount of the wafer W from the moment when the wafer is placed on the mounting surface until it is stabilized at 150 ° C., and 150 The temperature stabilization time until stabilization at ± 0.5 ° C. was measured.

Each result is as shown in Table 4.

As can be seen from Table 4, sample no. In the wafer heating apparatus shown in 41, 42, 51, and 52, since the thermal conductivity of the filler is small and the responsiveness is poor, the overshoot amount is slightly large as 1.2 to 1.6 ° C., and the temperature stabilization time is 39 to 39. It was bought a little length and 40 seconds.

Sample No. 49,50,60, because a large thermal conductivity of the filler, transmitted to the heat quickly temperature measuring element due to heat generation of the resistance heating element, the temperature stabilization time is bought. Long and 40 seconds.

On the other hand, the sample No. 2 in which the thermal conductivity of the filler is 8.3 to 150% with respect to the thermal conductivity of the plate-like ceramic body. 43-48 and No.54~59 is the wafer W is maintained at room temperature, poured into pressurized thermal device, overshoot amount of the wafer W to be stabilized from the moment placed on the placement surface to 0.99 ° C. 1. The temperature stabilization time until the temperature was as low as 1 ° C. or less and stabilized at 150 ± 0.5 ° C. was also 37 seconds or less, and even better results were obtained.

  Here, the influence of the porosity of the filler for fixing the temperature measuring element was investigated. The filler used is a polyimide resin in which carbon having an average particle size of 1.0 μm is dispersed, and the porosity of the filler is adjusted to 0.1 to 50% by adjusting the stirring speed at the time of mixing and the degree of vacuum defoaming. Adjusted between. The porosity was determined by separately solidifying the resin prepared at the same time, measuring the bulk specific gravity, and converting the difference from the theoretical density obtained from the mixing ratio. Using the filler thus adjusted, temperature measuring elements were fixed to the concave portions of the respective plate-like ceramic bodies, and wafer heating devices were produced.

Then, to measure the overshoot amount before the temperature cycle test and temperature stabilization time in the same manner as in Example 1. In the temperature cycle test, a temperature cycle in which the temperature was raised from 40 ° C. or less to 250 ° C. in 2 minutes and forced air cooling to 40 ° C. or less in 3 minutes was performed as one cycle. The evaluation method is the same method as in Example 1, and after the temperature cycle test of 10,000 times, the mounting surface of the wafer heating device is heated to 150 ° C. for 1 hour or longer, and then the wafer W maintained at room temperature is replaced with that of the wafer heating device. placed on the mounting surface, the temperature stabilization time to stabilize from the moment placed on the placement surface to 0.99 ± 0.5 ° C., measured One not a respective sample 5 times, and the maximum value and the measured value.

The results are shown in Table 5.

As can be seen from the results shown in Table 5 , the sample No. 61 shows that the temperature stabilization time from the moment when the wafer W maintained at room temperature before the temperature cycle test is put into the heating device to be stabilized at 150 ± 0.5 ° C. is 36 seconds. However, the result after a temperature cycle test of 10,000 cycles was 41 seconds. This is believed to be due to that exit from the recess of the filler caused by thermal expansion difference between you increase the number of temperature cycles and the plate-shaped ceramic body filler. Sample No. with a filler porosity of 60%. 69 also had a good temperature stabilization time of 37 seconds before the thermal cycle, but became 40 seconds after 10,000 temperature cycles.

  On the other hand, the sample No. with a porosity of 0.1 to 50% of the filler is used. In 62 to 68, the amount of change in temperature stabilization time due to the temperature cycle was small and stable. This can be determined that the pores improve the elasticity of the filler and absorb the stress due to the difference in thermal expansion between the filler and the ceramic substrate.

Here, the influence of the thermal expansion coefficient of the filler for fixing the temperature measuring element was investigated. Plate ceramics for each wafer heating apparatus using a filler in which the material of the plate ceramic body is aluminum nitride and the thermal expansion coefficient of the filler is changed to 1.5 to 14.3 × 10 ⁻⁶ / ° C. A temperature measuring element was fixed to the concave portion of the body, and a wafer heating apparatus was produced.

Thus by energizing the conductive terminals of the resulting wafer heating device to hold at 0.99 ° C., in the same manner as in Example 5, and the adjustment of the temperature line Tsu name. In addition, after removing the wafer and holding it for 60 minutes or more only with the wafer heating device, the wafer W maintained at room temperature is put into the heating device and is stabilized at 150 ± 0.5 ° C. from the moment it is placed on the mounting surface. the temperature stabilization time, measures not a One each sample five times to the maximum value and the measured value.

  Further, 10,000 temperature cycles were performed in the same manner as in Example 5, and the temperature stabilization time was measured. Specifically, the evaluation was performed using a filler obtained by dispersing a metal such as carbon, Al, or Cu in a polyimide resin having a thermal conductivity of 1 W / (m · K) as a filler.

The results are shown in Table 6.

As can be seen from the results shown in Table 6 , the sample No. 2 has a thermal expansion coefficient of 29% relative to the thermal expansion coefficient of the plate-like ceramic body. No. 71 having a thermal expansion coefficient ratio of 286%. 79 and the temperature stabilization time of the previous cycle is 34 seconds, but was excellent and 35 seconds, the temperature stabilization time after 10000 cycles 41 seconds, and was rather long 40 seconds. Sample No. Since 71,79 has a large ratio of thermal expansion coefficient, the movement of the temperature measuring element by thermal cycling occurs, the temperature stabilization time was slightly long Kuna'.

In contrast, a sample ratio above SL thermal expansion coefficient of forty-three to two hundred fourteen% No. 72-78 are No. Movement of the temperature measuring element caused by heat cycles from the unlikely to occur, such as 71,79, the temperature stabilization time is become longer fear has been found that good preferable reduced by temperature cycling.

It is sectional drawing which shows the wafer heating apparatus of this invention. It is a top view which shows the plate-shaped ceramic body of the wafer heating apparatus of this invention. It is sectional drawing which shows the temperature measuring element installation part of the wafer heating apparatus of this invention. It is sectional drawing which shows the conventional wafer heating apparatus.

1: Wafer heating device 2: Plate-like ceramic body 3: Placement surface 4: Insulating layer 5: Resistance heating element 6: Feeding portion 7: Conductive terminal 8: Elastic body 10: Temperature measuring element 11: Support body 21: Recess 22 : Filler 81: Control unit 82: Storage unit W: Semiconductor wafer t: Thickness

Claims (5)

Wafer heating in which a plurality of strip-like resistance heating elements are formed on the surface or inside of a plate-like ceramic body, a recess is provided at a position corresponding to each resistance heating element of the plate-like ceramic body, and a temperature measuring element is provided in the recess. in the device, at least one of the plurality of band-shaped resistive heating element disposed on the outermost circumference of the plate-shaped ceramic body is provided with a temperature measuring element in the center of the region surrounding the resistance heating element, the temperature measuring element The wafer heating apparatus is characterized in that the power density in the vicinity of is lower than the average power density of the strip-shaped resistance heating element corresponding to the temperature measuring element . 2. The wafer heating apparatus according to claim 1, wherein a power density in the vicinity of the temperature measuring element is 40 to 90% of an average power density of the resistance heating element. On SL temperature measurement element to claim 1 or 2, characterized in that fixed to the upper Symbol recess with a filler having a 8.3 to 150% of the thermal conductivity with respect to the thermal conductivity of the plate-shaped ceramic body The wafer heating apparatus as described. The porosity of the above Symbol filler is 0. 4. The wafer heating apparatus according to claim 3, wherein the temperature is 1 to 50%. Wafer heating apparatus according to claim 3 or 4 thermal expansion coefficient of the upper Symbol filler is characterized by a 43 to 214% relative to the thermal expansion coefficient of the upper Symbol plate-shaped ceramic body.

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